Pinpoint Test I: All The Stoplamps Are Inoperative

Stoplamps

Pinpoint Test I: All The Stoplamps Are Inoperative

Refer to Wiring Diagram Set 90, Turn Signal/Stop/Hazard Lamps for schematic and connector information Electrical Diagrams.

Normal Operation

The stoplamp switch is supplied voltage from the Smart Junction Box (SJB). When the brake pedal is applied, the stoplamp switch routes voltage back to the SJB (Smart Junction Box) and the high mounted stoplamp. The SJB (Smart Junction Box) provides voltage to the rear lamps when it receives input from the stoplamp switch indicating that the brake pedal is applied.

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- Stoplamp switch

- SJB (Smart Junction Box)

PINPOINT TEST I : ALL THE STOPLAMPS ARE INOPERATIVE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

I1 CHECK FOR VOLTAGE TO THE STOPLAMP SWITCH

- Ignition OFF.

- Disconnect: Stoplamp Switch C278.

- Measure the voltage between the stoplamp switch C278-1, circuit SBP02 (YE/RD), harness side and ground.





Is the voltage greater than 10 volts?

Yes
GO to I2.

No
VERIFY the SJB (Smart Junction Box) fuse 2 (15A) is OK. If OK, GO to I3. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams.

I2 BYPASS THE STOPLAMP SWITCH

- Connect a fused jumper wire between the stoplamp switch C278-1, circuit SBP02 (YE/RD), harness side and the stoplamp switch C278-4, circuit CCB08 (VT/WH), harness side.





Are the stoplamps illuminated?

Yes
REMOVE the jumper wire. INSTALL a new stoplamp switch. REFER to Stoplamp Switch . TEST the system for normal operation.

No
REPAIR circuit CCB08 (VT/WH) for an open. TEST the system for normal operation.

I3 CHECK THE STOPLAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

- Disconnect: SJB (Smart Junction Box) C2280D.

- Measure the resistance between the stoplamp switch C278-1, circuit SBP02 (YE/RD), harness side and the SJB (Smart Junction Box) C2280D-13, circuit SBP02 (YE/RD), harness side.





Is the resistance less than 5 ohms?

Yes
GO to I4.

No
REPAIR SBP02 (YE/RD) for an open. TEST the system for normal operation.

I4 CHECK FOR CORRECT SJB (Smart Junction Box) OPERATION

- Disconnect all the SJB (Smart Junction Box) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the SJB (Smart Junction Box) connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new SJB (Smart Junction Box). TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.